Refrigerating apparatus



Sept. 26, 1939,

c. w. KUHN 2,174,037

REFRIGERATING APPARATUS Filed April 26, 1957 '-,DEFROST 29 41 Patented Sept. 26, 1939 UNITED STATES PATENT OFFICE Cutler-Hammer, Inc., poration of Delaware Milwaukee, Wis, a cor- Application April 26 1937, Serial No. 138,927

6 Claims.

This invention relates to refrigerating apparatus and more particularly to control mechanisms'for such apparatus.

Electric refrigerators are usually controlled by a device having adjustable cold controlmeans associated therewith for maintaining the cooling unit of the refrigerator at selected temperature values such as are required for ordinary refrigerating purposes. In some instances such control devices are also provided with semiautomatic control means including manual control means for rendering the device effective to raise the temperature of the cooling unit to a given value for defrosting or to lower the temperature thereof to a given value for quick freezing and automatic means for restoring the control device to normal condition upon attainment of such temperature values.

The present invention has among its objects to provide a refrigerator control device of the aforesaid character having a simplified and generally improved semi-automatic defrosting and quick freeze control mechanism associated therewith.

- Another object is to provide a control device of the aforesaid character in which a single loading springserves to'effect cold control and also semi-automatic quick freeze and defrost control.

Another object is to provide a control device of the'aforesaid character which provides a fixed defrosting temperature and a fixed quick freeze temperature regardless of the setting of the cold control means.

' Various other objects and advantages of the invention will hereinafter appear.

' The accompanying drawing illustrates an embodiment of the invention which will now be described, it being understood that various modiiicatlons may be made'in the embodiment illustrated without departing from the spirit and scope of the appended claims.

In the drawing,

Figure 1 is a side view of a refrigerator control device embodying the invention, a portion of the enclosing casing being broken away and portions of the operating mechanism being shown in section.

Figs. 2 and 3 are fragmentary. side elevational views of the control device shown in Fig. 1 illustrating the semi-automatic control means in defrosting and quick freeze positions, and

Figs. 4 and 5 are fragmentary sectional views taken substantiallyon lines l-.l and 5-! respectively of Fig. 1.

Referring to Fig. 1, the invention is shown in connection with a refrigerator control device of the type shown in my copending application Serial No. 108,804, filed January 29, 1934, but it may be used in connection with control devices of other types.

Briefly the refrigerator control device shown in Fig. 1 includes a box enclosing casing i having a switch unit 2 and a fluid condition responsive device 3 mounted therein. Said switch unit includes an insulating base 4 which carries a l pivoted bridging contact element 5 and a pair of cooperating stationary contacts, one of which is illustrated at 6. Contact element 5 is movable with a snap action into and out of=engage-- ment with its cooperating stationary contacts by 15 an over center spring I, said spring being operatively connected to an operating knob 8 slidably mounted within an opening in the front wall of easing i. The switch unit 2 also has a free tripping overload mechanism associated there'- with which acts under overload conditions to move contact element 5 into open position, through the medium of the spring 1 and which is resettable by the knob 8. However, the overload mechanism need not be considered for the "u purpose of this application.

The fluid condition responsive device I includes a bellows l0 secured to the rear wall of easing. l and having a. connecting pipe extension II on the rear end thereof. The pipe il may go be connected to the low pressure side'of the refrigerator to provide for operation of the bellows by pressure in that part of the apparatus or it may contain an expansible gas and be arranged at a point contiguous to the cooling unit of the g5 refrigerator where the temperature and consequently the pressure within the pipe and bellows varies in accordance with operations of the refrigerator.

The front end of bellows l0 bears against a w lever I! having a vertically arranged arm l2 which is pivoted at I! upon a bracket I4 fixed within the casing i. A loading spring I! engages arm if of lover I! to oppose-expansive movements of the bellows I0 and said lever has 45 a snap operating mechanism associated therewith for moving bridging contact 5 into and out of circuit closing position. Such operating mechanism includes a lever i1 pivoted at l8 upon bracket I4 and an over center spring l9 which is 5 held under compression between the free end of arm I! and the free end of lever l1. Movement of lever i1 is limited in one direction by insulating base 4- and in an opposite direction by an adjustable stop 20 secured to the rear wall a of casing I and said lever is arranged to operate the movable contact element 5 through the medium of an insulating member 2! slidably mounted within a recess in insulating base 4.

Upon a decrease in temperature, bellows Ill contracts under the action of spring l5 and for a given low temperature value determined by the degree of compression of spring l5 lever I2 assumes a position wherein the axis of spring I9 is located to the left of pivot l8 whereupon lever I7 is moved with a snap action out of the position shown in Fig. 1 to effect opening of bridging contact 5 against the action of spring l. Upon an increase in temperature, bellows l0 expands against the action of spring l5 and for a given high temperature value also determined by the setting of spring l5 lever l2 assumes a position wherein the axis of spring 09 is located to the right of pivot 68 whereupon lever it moves with a snap action into the position shown in Fig. l to permit reclosure of contact element 5 under the action of spring ll. As is apparent, increasing the degre of compression of spring 95 raises the temperature values at which contact element 5 is moved into circuit closing and circuit opening positions, while decreasing the degree of compression of said spring has an opposite effect.

Spring 05 is held under compression between arm l2 of lever l2 and a lever 22 which is pivotally mounted as shown at 23 upon the upper wall of casing ll. Lever 22 bears against a nut 24 carried by a screw 25 rotatably mounted within an opening in the front wall of casing i. Nut 24 is held against turning by a rib 26 on casing l which engages within a recess in said nut and screw 25 is held against forward movement under the action of spring 55 by a shoulder 21 thereon which engages the front wall of casing l. The front end of screw 25 has a dial pointer 28 fixed thereto, and as is apparent the screw 25 is adjustable by the dial pointer 28 to adjust nut 24 and lever 22 axially with respect to said screw for variation of the degree of compression of loading spring I 5. The dial pointer 28 is movable over a suitable dial which may be formed on the front face of casing I to indicate the setting of loading spring I5, and as is the usual practice said dial pointer has a limited range of adjustment to provide for starting and stopping of the refrigerator at selected temperature values within a given normal range.

The above described control device is provided with a semi-automatic defrost and quick freeze control mechanism. Such mechanism includes a control lever 32 having an enlarged hub 33 which is arranged within an opening in the front wall of easing l and is rotatably mounted upon a pin 34 carried by said casing. As shown in Fig. 5, lever I 2 is provided with spaced forwardly extending arms I 2 and I2 which are located on opposite sides of the hub 33 on control lever 32, and said hub is provided with spaced slots for receiving a pair of links 35 and 36. Links 35 and 36 have their front ends pivotally secured to hub 33 by pins 31 and 38 respectively, and each of said links has a slot on its inner end for receiving a pin 39 fixed to lever 22. Pin 31 is arranged below arm l2 of lever 12 and is provided with a projection 31 for engaging said armon the under side thereof. Pin 38 is arranged above the arm I2 and is provided with a projection 38 for engaging said arm on the upper side thereof.

With control lever 32 in the position shown in Fig. l the pivcu pin projections 31 and 38 are spaced with respect to their associated arms H and i2 to permit unobstructed movement of lever l2 between positions for opening and closing contact element 5. Also with control lever 32 in the position shown in Fig. 1 pin 39 on lever 22 slides within the slots on the inner ends of links 35 and 36 upon adjustment of said lever by dial pointer 28.

Control lever 32 is movable out of the position shown in Fig. 1 into a defrost position wherein the same engages a stop surface 4| on the front wall of casing I. Upon movement of control lever 32 into defrost position link 36 engages pin 39 on lever 22 to move said lever away from nut 24 into the position shown in Fig. 2. Spring i5 is thus compressed to increase the loading effect thereof, and as is apparent from Fig. 2 link 36 is so located that control lever 32 is yieldingly held in engagement with stop surface ll under the action of said spring. Also upon movement of control lever 32 into defrost -position pin projection 38 engages the upper side of arm H2 of lever l2 to move said lever into circuit opening position if the same is not already in such position. Lever l2 remains in circuit opening position under the action of spring l5 until the temperature of the refrigerator rises to a given abnormal value which is sufficiently high to effect defrosting of the cooling unit. When the temperature rises to such abnormal temperature value bellows 3 acts against the action of spring l5 to move lever l2out of the position shown in Fig. 2. Arm [2 of lever l2 then engages pin projection 38" to move control lever 32 towards off position, and as is apparent upon a slight movement of said control lever out of defrost position link 36 assumes a position wherein said control lever is returned with a snap action to off position under the action of spring l5. Upon return of control ,lever 32 to off position lever l2 moves into its circuit closing position to restart the refrigerator and lever 22 moves into engagement with nut 24 to render the control device operative to maintain the temperature of the refrigerator between temperature limits determined by the setting of dial pointer 28.

Control lever 32 is also movable out of the position shown in Fig. 1 into a fast freeze position shown in Fig. 3. Upon movement of control lever 32 into its fast freeze position the link 35 engages pin 39 on lever 22 to move said lever away from nut 24 into the position shown in Fig. 3 and the projection 31 of pivot pin 31 engages the underside of arm l2 to move operating lever l2 into its circuit closing position if the same is not already in such position. With control lever 32 in its fast freeze position spring [5 acts through the medium of link 35 to bias said control lever in a clockwise direction whereby the pivotpin projection 31 acts on arm 12 to exert an upward pressure thereon. The upward pressure on arm l2 opposes the force exerted by spring [5 on arm l2. and the parts are so designed that the pressure on arm l2 reduces the loading effect of spring IS on lever l2 to an abnormally low value. Lever l2 remains in the circuit closing position shown in Fig. 3 until the temperature of the refrigerator drops to a given abnormal quick freezing temperature. Bellows 3 is then compressed under the action of spring l5 and the arm I2 of lever l2 acts through the medium of pin projection 31- to move control lever 32 towards off position. As is apparent, upon a slight movement tion, a switch,

of control lever 32 out of fast freeze position link 36 is moved into a position wherein said control lever is returned with a snap action to off position under the action of spring l5. Upon return of control lever 32 to off position the loading effect of spring l5 upon lever I2 is increased and said lever moves into switch opening position to stop the refrigerator. Also lever. 22 moves into engagement with nut 24 to provide for operation of the refrigerator at temperature values determined by the setting of dial pointer 28.

In connection with the foregoing it should be noted that when control lever 32 is in either its defrosting or fast freeze position the same can be manually moved to off position at any time to restore the control device for operation in accordance with the setting of dial pointer 28. Also it should be noted that opening and closure of contact element 5 by control lever 32 is efiected with a snap action.

What I claim as new and desire to secure by Letters Patent is:

1. In a refrigerator control device, in combination, a switch, thermo-responsive operating means therefor, a single loading spring associated with saidthermo-responsive operating means, an adjl stment control for varying the effect of said loading spring to provide for operation of said switch at selected temperature values within a given normal range, and mechanism for varying the loading effect of said spring to provide a given operation of said switch at a predetermined abnormal temperature value outside of said normal range regardless of the setting of said adjustment control.

2. In a refrigerator control device, in combinathermo-responsive operating means therefor, a single loading spring asso-' ciated with said thermo-responsive operating means, an adjustment control for varying the loading effect of said spring to provide for operation of said switch at selected temperature values within a given normal range, and means for varying the loading effect of said spring to provide a given operation of said switch at a predetermined abnormal temperature outside of said normal range and for restoring said spring to the setting determined by said adjustment control upon operation of said switch at said predetermined abnormal temperature.

3. In a refrigerator control device, in combination, a switch, temperature responsive operating means therefor having a single loading spring associated therewith, an adjustment control for varying the loading effect of said spring to provide for operation of said switch at selected temperatures within a given normal range, manual means'for increasing the loading effect of said spring to provide for closure of said switch at a predetermined defrosting temperature outside of said range, and means for restoring said manual means to normal position upon opening of said, switch at said predetermined defrostin temperature.

4. In a refrigerator control device. in combination, a switch, temperature responsive operating means therefor, a loading spring associated with said temperature responsive operating means normally set to provide for operation of said switch at temperature values within a given nor- .mal range, manual means for varying the loading effect of said spring to selectively provide for operation of said switch at different predetermined abnormal temperatures outside of said range, and means for restoring said manual control means to normal condition upon operation of said switch at either of said abnormal temperatures.

5. In a refrigerator control device, in combination, a control switch, temperature responsive operating means therefor, a single loading spring associated with said temperature responsive operating means, an adjustment control for varying the loading effect of said spring to provide for operations of said switch at selected temperatures within a given normal range, a control part movable between off and defrost positions, mechanism actuated upon movement of said control part into its defrost position for modifying the loading effect of said spring to provide for closure of said switch at a substantially fixed defrosting temperature outside of said normal range, said control part when moved into defrost position being releasably held therein by said mechanism under the action of said loading spring, and means associated with said temperature responsive operating means for moving said control part out of defrost position upon closure of said switch at said substantially fixed defrosting temperature.

6. In a refrigerator control device, in combination, a control switch, temperature responsive operating means therefor, a single loading spring associated with said temperature responsive operating means, an adjustment control for varying the loading effect of said spring to provide for operation of said switch at selected temperatures within a given normal range, a control part movable in opposite directions out of an intermediate oif position into extreme defrost and fast freeze positions, mechanism uninfluenced by the setting of said adjustment control and associated with said control part for modifying the loading effect of said spring to provide for closure of said switch at a substantially fixed defrosting temperature outside of said normal range upon movement of said control part in its defrost position and for opening of said switch at a substantially fixed fast freeze temperature outside of said normal range upon movement of said control part into its fast freeze position, said control part when moved into its defrost or fast freeze positions being releasably held therein by said mechanism under the action of said spring,

and means associated with said temperature responsive operating means for returning said control member to off position upon operation of said switch at said defrosting or fast freeze temperatures.

CLARENCE W. KUHN. 

